1. Field of the Invention
The present invention relates to an image processing apparatus, and in particular, to an image processing system for executing image processings of an image recorded on a color photographic film after development.
2. Description of the Related Art
Color photographic films, such as a color negative film or a color reversal film, comprise a blue-light-photosensitive layer for forming a yellow dye image due to blue light exposure, a green-light-photosensitive layer for forming a magenta dye image due to green light exposure, and a red-light-photosensitive layer for forming a cyan dye image due to red light exposure.
At the time of photographic processing of a color negative film, a developer is oxidized in the process of reducing silver halide particles containing a latent image into silver, and a dye image is formed by coupling of the oxidized developer and a dye-forming coupler. Conventionally, undeveloped silver halide is eliminated in a fixing process, or an undesirable developed silver image is eliminated in a bleaching process.
Recently, convenience in such photographic processing of a color negative film has been called for more and more strongly. For example, Japanese Patent Application Laid-Open (JP-A) No. 6-295035 discloses an image forming method for extracting the image information representing image wise exposure for each of the red (R), green (G), and blue (B) color parts from a silver halide color photograph element, that is, from a silver image, without forming a dye image by the black and white development of a color photographic film.
However, an ordinary color photographic film is designed so as to have an image with appropriate color gradation R, G, B transmission densities at the time of normal development. That is, a color photographic film is designed for providing a dye image appropriately, and is not designed for appropriately providing a silver image, which is not to be used originally for image information. Thus, in the case in which a color photographic film is subjected to black and white development or to color development and a silver image or a color image is read, appropriate color reproduction and gradation reproduction are not possible.
Moreover, since the ratio of the dye image and the developed silver differs depending on the type of the film, the exposure level, and the like, the read images cannot be corrected uniformly.
Furthermore, since the reflection density and the transmission density are in anon-linear relationship, in a case in which both reflection reading and transmission reading are used, the gray balance cannot be corrected by a simple correction.
Moreover, the problem of color mixing occurs in the reflection reading due to the influence by the lower layers. Since the extent thereof differs depending on the type of the film, the color mixing cannot be corrected uniformly.
Furthermore, since the concentration of unnecessary substances remaining in a color photographic film after black and white development, the concentration of the silver halide, and the concentration of the anti-halation layer produced by the colloid silver differ in accordance with the type of the film, they cannot be corrected uniformly.
A silver image can be obtained by irradiating a light beam from the front side and the back side of a color negative film, and detecting the light reflected from and the light transmitted through the front side (emulsion surface side) of the color negative film and the back side (base surface side thereof).
However, unlike color paper, an ordinary color photographic film does not contain a layer including titanium oxide or the like having a high reflectance, and thus ordinary color photographic film cannot reflect light efficiently. Therefore, in order to read an image with a high S/N (signal/noise) ratio, a large amount of light should be irradiated onto the film. In particular, in the case of reading reflected light from the base surface side, since the anti-halation layer comprising a colloid silver attenuates the light, an even larger amount of light should be irradiated.
However, in the case in which a large amount of light is irradiated, heat may be generated so as to deform or damage the film, and thus, the amount of irradiated light cannot be increased. Moreover, as compared with a case of reading transmitted light, in reading reflected light, generation of flare and deterioration of sharpness due to the multiple reflections in the layers are conspicuous. Furthermore, the sharpness is deteriorated also due to the color offset caused by the positional offset between a sensor for reading out the reflected light and a sensor for reading out the transmitted light.
Moreover, in this case, the silver image information of the intermediate layer can be obtained by subtracting the silver image information based on the light reflected from the front side and the back side of the color negative film, from the silver image information based on the light transmitted through the color negative film.
However, since the image information of the intermediate layer is obtained by subtracting the silver image information based on the light reflected from the front side and the back side of the color photographic film from the silver image information based on the light transmitted through the color photographic film, appropriate color reproduction is even more difficult to achieve.